Direct determination of the local Hamaker constant of inorganic surfaces based on scanning force microscopy

2014 ◽  
Vol 141 (16) ◽  
pp. 164707 ◽  
Author(s):  
Brad A. Krajina ◽  
Lakshmi S. Kocherlakota ◽  
René M. Overney
Keyword(s):  
Direct Determination ◽  
Scanning Force Microscopy ◽  
Hamaker Constant ◽  
Force Microscopy ◽  
Scanning Force

Anisotropy of Nanoindentation – a tool for the determination of nanocrystal orientation ?

2003 ◽  
Vol 779 ◽  
Author(s):  
David Christopher ◽  
Steven Kenny ◽  
Roger Smith ◽  
Asta Richter ◽  
Bodo Wolf ◽  
...  
Keyword(s):  
Crystal Surface ◽  
Scanning Force Microscopy ◽  
Depth Range ◽  
Dislocation Loops ◽  
Force Microscopy ◽  
Pile Up ◽  
Out Of Plane ◽  
Scanning Force ◽  
Dynamics Simulations

AbstractThe pile up patterns arising in nanoindentation are shown to be indicative of the sample crystal symmetry. To explain and interpret these patterns, complementary molecular dynamics simulations and experiments have been performed to determine the atomistic mechanisms of the nanoindentation process in single crystal Fe{110}. The simulations show that dislocation loops start from the tip and end on the crystal surface propagating outwards along the four in-plane <111> directions. These loops carry material away from the indenter and form bumps on the surface along these directions separated from the piled-up material around the indenter hole. Atoms also move in the two out-of-plane <111> directions causing propagation of subsurface defects and pile-up around the hole. This finding is confirmed by scanning force microscopy mapping of the imprint, the piling-up pattern proving a suitable indicator of the surface crystallography. Experimental force-depth curves over the depth range of a few nanometers do not appear smooth and show distinct pop-ins. On the sub-nanometer scale these pop-ins are also visible in the simulation curves and occur as a result of the initiation of the dislocation loops from the tip.

scholarly journals Determination of preferential binding sites for anti-dsRNA antibodies on double-stranded RNA by scanning force microscopy

RNA ◽  
2000 ◽  
Vol 6 (4) ◽  
pp. 563-570 ◽  
Author(s):  
MICHAEL BONIN ◽  
JÜRGEN OBERSTRAß ◽  
NOEMI LUKACS ◽  
KATJA EWERT ◽  
EGBERT OESTERSCHULZE ◽  
...  
Keyword(s):  
Binding Sites ◽  
Scanning Force Microscopy ◽  
Double Stranded Rna ◽  
Force Microscopy ◽  
Preferential Binding ◽  
Scanning Force

scholarly journals Practical Limitations to Indentation Testing of Thin Films

1997 ◽  
Vol 505 ◽  
Author(s):  
J. A. Schneider ◽  
K. F. McCarty ◽  
J. R. Heffelfinger ◽  
N. R. Moody
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Scanning Force Microscopy ◽  
Indentation Testing ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Low Load ◽  
Scanning Force ◽  
Deposited Films

ABSTRACTA method that is becoming increasingly common for measuring the mechanical behavior of thin films is low-load indentation testing. However, there can be complications in interpreting the results as many factors can affect hardness and moduli measurements such as surface roughness and determination of the indentation contact area. To further our understanding, the mechanical properties of thin (50 nm) films of AlN on sapphire substrates were evaluated using a scanning force microscopy (SFM) based pico-indentation device to allow imaging of the surface and indentations. Our primary emphasis was the types of problems or limitations involved in testing very thin, as deposited films in which properties are desired over indentation depths less than 50 nm.

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